News and Events

BLOG: Taking the power of expectations to the
patient

How easily can you be influenced in your
expectations? To what degree do your expectations
influence you, for example, your symptoms when
being ill or the effects of treatment? And how can
such expectations be applied to optimize patient
care?

The impact of expectations

Perhaps you recognize the experience that taking a
painkiller when you have a ferocious headache
immediately decreases your pain, even if the drug
cannot yet have influenced your physiology. There
are many fundamental lab studies that show
convincingly that our expectations have a powerful
impact on our experiences. Telling people what to
expect, for example how painful a specific
stimulus will be, influences the pain that people
actually experience, either for the better or for
the worse. Also, influencing people’s
expectations by repeatedly pairing two stimuli
(e.g., pairing a specific drink with taking a
painkiller) can lead to the previously neutral
stimulus (the drink) triggering a similar response
(pain relief) on its own, without the actual
stimulus (painkiller) being present. This
phenomenon, classical conditioning, is best known
from Pavlov’s dogs. These learning
mechanisms can induce both positive and negative
expectations, resulting in positive (placebo) and
negative (nocebo) effects.

Within our research group at the Health, Medical, and
Neuropsychology Unit, we are conducting
fundamental research into placebo and nocebo
effects, subsidized by grants from the European
Research Council and the Netherlands Organisation
for Scientific Research awarded to Prof. Andrea Evers. In these studies,
in which I have been actively involved from their
conception, a large group of talented PhD-studentsare
examining various combinations of learning
mechanisms in search of the ideal way to influence
physical symptoms, such as pain, itch, and
fatigue. There is still much more to learn, for
instance by examining how expectancy learning
impacts our brain. We think, however, that our
current state of knowledge can be put into
practice, by looking into the applicability of
these learning processes for patients.

The influence of expectations in
patient populations

A number of fascinating studies on expectations
have already been performed in patient groups. It
has been shown, for instance, that the
effectiveness of a painkiller after surgery is
dramatically higher when patients are aware that
they are being given the painkiller (open
application) then when it is administered by a
machine at an unknown time (hidden application).
In another study, up to a year after ‘sham
surgery’ on a meniscal tear, patients showed
the same decrease in pain and the same increase in
walking ability as patients who had actual
surgery. When it comes to nocebo effects, a
prominent example in clinical practice is the
nausea that patients undergoing chemotherapy often
experience already in response to a specific sight
or odour (e.g., of the hospital). Moreover,
telling patients that a certain procedure will be
painful (which is standard practice) leads to the
experience being perceived as more painful than if
the pain is not explicitly mentioned. Thus,
these studies clearly show the impact of
expectations in clinical practice.

Expectations in patients with chronic
pain

If you are a patient with, for instance, chronic
pain symptoms, you will probably have had several
learning experiences. Since there is no
‘gold standard’ treatment for chronic
pain, most patients have negative experiences with
unsuccessful treatments. Also, in order not to get
patients’ hopes up too much, physicians may
communicate that there is a high chance that a new
treatment will not ‘work’. All of this
information will lead to negative expectations
that do not contribute to a successful symptom
course or treatment outcome for patients. However,
negative treatment experiences cannot be
prevented, unfortunately, and it would be
unethical for physicians to provide overly
optimistic expectations regarding new treatment or
not to inform patients about important potential
side effects. With these dilemmas in mind, we are
looking for ways to take account of and try to
change these existing expectations in an ethical
way. For example, research has shown that placebos
are effective even when patients are informed
about receiving a placebo, as long as the
mechanisms behind its effects are explained
(open-label placebo). Much more research is needed
in this area to examine how we can optimally
translate our lab-based knowledge to clinical
practice.

Expectations as triggers and
intervention opportunities in chronic
pain

We are currently at the start of two major
projects in patients with fibromyalgia (chronic
widespread pain). In these projects, part of
Andrea Evers’s VICI-grant, we
will delve into the role of expectations for
patients’ pain symptoms. The first project,
conducted by Merve Karacaoglu, will examine whether
the sensitivity to learning negative associations
(nocebo conditioning) can predict pain progression
over time. This sensitivity to nocebo effects will
be examined by applying pressure pain stimuli that
most closely resemble patients’ daily pain
experiences. If this study finds that
patients who are more sensitive to nocebo learning
show more pain progression, this would enable us
to identify patients at risk for symptom
progression at an early stage. The second project,
carried out by Simone
Meijer, will examine the effectiveness of a
new treatment method. The main idea is to
attenuate previously learned negative associations
related to pain. To do this, we will first
condition participants so that they learn a
connection between a placebo device and pain
stimuli (nocebo conditioning). Subsequently, we
will ‘overwrite’ (countercondition)
this association by coupling the placebo device
with low pain. By repeating this
counterconditioning procedure over a number of
weeks and by generalizing exercises to be carried
out by the participants at home, we aim to
decrease their pain symptoms in daily life. All of
this will be performed in an open-label fashion,
thus allowing actual implementation. These two
studies will be an important step forward for our
knowledge on the role of learning processes in
patients with chronic somatic symptoms, and
provide the potential to influence patients’
expectations by means of an intervention.